The UK is set to be hotter than some Spanish holiday hotspots this weekend, with temperatures reaching near to 30C. This weather firmly puts us in summer territory and calls for barbecues, swimming pools and plenty of suncream. But when is the first day of summer officially?
There are two ways to decide when the first day of summer is – one meteorological and the other astrological.
The beginning of meteorological summer is based on the month of the year, with the 12 months split into four.
Spring lasts through March, April and May, summer is June, July and August, autumn is September, October, November and winter is December, January and February.
According to meteorological definitions, the first day of summer will be Saturday, June 1.
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However, the astronomical definition of the seasons determines the time of year based on the Earth’s axis and how it is tilted.
This means for astronomical standards summer begins on Friday, June 21.
Friday, June 21 is also the date of the summer solstice, on which the longest day of the year occurs.
According to Earthsky.org: “A solstice is an astronomical event, caused by Earth’s tilt on its axis and its motion in orbit around the sun.”
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During the June solstice, Earth is positioned in orbit so that the North Pole is leaning most toward the Sun.
This means the Sun will rise at its earliest, and set at it’s latest creating the longest day of 2019 for the Northern Hemisphere.
For those in the Southern Hemisphere, the June solstice represents the shortest day of the year and the start of winter.
Ancient cultures knew that the Sun’s path across the sky, the length of daylight, and the location of the sunrise and sunset all shifted in a regular way throughout the year.
They built monuments, such as Stonehenge, to follow the Sun’s yearly progress.
Today people still gather at Stonehenge during winter and summer solstices to witness the sun’s rise above the stones.
After the summer solstice, days begin to steadily grow shorter until the winter solstice, which represents the shortest day of the year.
This year the winter solstice falls on Sunday, December 22.